1. Field of the Invention
The present invention relates generally to vehicle sealing or plugging devices. More particularly, the present invention discloses a composite plug assembly and related method of manufacture for use in particular during vehicle manufacture. Such plugs are capable of being designed for such varied purposes as sealing pre-formed vehicle drainage apertures, being applied in layer form to provide heat and sound insulation to such as vehicle undercarriages, as well as being configured in a wrapping or rolled three-dimensional arrangement for inserting in a longitudinally extending fashion for providing sealing and baffling characteristics to such as elongated vehicle pillars and the like. The composite material can also be used as a formed panel such as a door inner panel, hood or deck lid inner panel, roof bows etc.
2. Description of the Prior Art
The prior art is well documented with examples of closure and plug assemblies for use with vehicles. In particular application, vehicle manufacture contemplates for providing for drainage of a conventional vehicle paint application in the manufacturing process. Upon finished manufacture of the vehicle, it is desirous to plug or otherwise seal these xe2x80x9cengineeredxe2x80x9d apertures.
Examples of prior art sealing plugs and devices include U.S. Pat. Nos. 4,700,981 and 4,817,262, both issued to Seylor, and each of which teaching a paint drain closure and vehicle panel in the form of a one-piece sheet metal plug of inverted hat-shaped configuration (see FIG. 17 in particular). The closure plug in each instance is preferably disclosed as being formed of a deformable sheet metal and is supported and inserted, preferably through the use of a magnetically supporting and applicating tool, into the floor pan/panel opening in the vehicle body and prior to being mechanically sealed. Alternatively, a baking cycle is employed to soften and expand a sealant ring in order to produce a permanent adhesive bond between the parts. The plugs in Seylor further teach the provision of such as elongated annular ribs formed integrally with the side walls of the plugs and which, upon rotation of the inserted plug, are urged into a locking position beneath associated tabs or shoulders of the apertured panel to which it is applied.
U.S. Pat. No. 4,494,671, issued to Moore, teaches an auto body panel hole closure including a plate with dimensions complementary to a hole and a gasket member secured to the top of the plate and including a somewhat larger dimension than the hole. The gasket further includes a first or bottom side low melt layer and a second or top side copolymer layer. Upon exposure to elevated temperatures during baking, the gasket melts over the plate and adheres to the panel to create a seal between the plate and the panel.
U.S. Pat. No. 5,267,667, issued to Cozzani, teaches a plug adapted to be fixed by a hot melt adhesive into an opening in an auto body plate and which further includes a molded plastic material body and a bead of hot melt adhesive deposited onto a peripheral surface of the body and around a surface transverse to the peripheral surface. The body further includes a snap-fastener blade having an insertion ramp and a retaining lip such that the insertion ramp bears against the edge of the opening upon placement of the plug.
U.S. Pat. No. 3,606,446, issued to Leslie, teaches a drain hole plug assembly including the provision of a retainer plug with a plug body portion inserted into a drain hole of a panel and to be secured therein. The retainer plug supports a flexible washer serving as a flap valve and which is retained against an outer face of the panel by an annular flange. The flexible washer is protected from heat by an annular flange on the plug retainer which extends outwardly and is spaced from the flexible washer.
An additional and large grouping of similar patents are referenced in the prior art and include such as U.S. Pat. No. 5,505,324, issued to Danico, and which teaches a hole plug with heat expansible material. U.S. Pat. No. 4,290,536, issued to Morel, teaches a dish plug type seal with elastic collar and peripheral cord which is thermofusible to secure about aperture. U.S. Pat. No. 4,363,420, issued to Andrews, teaches a sealing plug with abutting flange portion and flowable sealant material which, when heated to a melting temperature below the melting point of the plug material, flows in order to adhere between an edge surface of an associated panel apertures and at least part of an insert portion. Still additional prior art patents of interest include Cieslik U.S. Pat. No. 5,040,803 (expandable sealant plug), Heinz U.S. Pat. No. 3,382,889 (sealing cap for vehicle body drain and including annular undercut rib), Dozois U.S. Pat. No. 3,935,686 (mechanically collapsible drain plug), and Emmerson U.S. Pat. No. 3,701,560 (auto vehicle body access and drain plug).
The present invention discloses a composite plug assembly and related method of manufacture for use in particular during vehicle manufacture. The composite assembly and method of the present invention is a distinct improvement over the prior art in that it is the first to provide a mesh screen substrate in use with a thermoplastic/thermoset material and in order to increase the durability and performance (these including sealing, structural, and adhering) characteristics of the composite plug.
As also previously described, such plugs are capable of being designed for such varied purposes as sealing pre-formed vehicle drainage apertures, being applied in layer form to provide heat and sound insulation to such as vehicle undercarriages, as well as being configured in a formed or rolled three-dimensional arrangement for inserting into and/or attaching in a cavity for providing sealing and baffling characteristics to such as elongated vehicle pillars and the like.
In every variant, the composite assembly includes the provision of a selected thermoplastic/thermoset material, hereinafter referred to as a sheet, having a selected length, width and thickness if desired. A sheet of a mesh substrate of a selected length, width and thickness, such as constructed from a suitable metal or metal alloy, is substantially encapsulated by the thermoplastic/thermoset material upon first arraying the heated sheet against such as an upper surface of the mesh substrate and then applying pressure at a first heating stage at a selected temperature range.
The resultant encapsulating thermoplastic/thermoset sheet (with interiorly disposed mesh substrate) substantially retains its initial configuration. It is however also envisioned that the encapsulating composite sheet and substrate may further be formed into a three-dimensional shape, such as a plug, through the application of a suitable stamping or die forming operation and for particular use in securing to and sealing such as a vehicle paint drainage aperture as previously described.
A laterally directed projection, such as a rim, may be formed into a recessed cup portion of the defined plug shape. Upon fitting the recessed cup into the vehicle aperture, and seating the encircling rim onto the vehicle surface proximate the opening, a secondary heating application is applied, beyond the softening point of the thermoplastic/thermoset material, and which will cause the material to become sufficiently molten so as to flow into and around the aperture and surrounding vehicle (plate) surface area. The thermoplastic/thermoset material may further exhibit a desired coefficient of thermal expansion and so that, upon application of the secondary heating stage, expands to the point that it adequately bonds and seals such as the vehicle opening.
As also previously described, the composite material is capable of being applied in layer form to provide heat and sound insulation to such as vehicle undercarriage or other suitable surface(s) of the vehicle. A further variation of the encapsulating mat configuration of the thermoplastic/thermoset material provides for an apertured section to be formed within the mat configuration, thus revealing the underlying mesh substrate.
The mat configuration is then welded in place or has holes pierced into it through which push-in or screw type fasteners are used to hold in place. The mat configuration is placed over a stripped or coated and substantially planar metal surface associated with a vehicle body and, upon application of the secondary heating stage (such as again typically occurring during such as a conventional paint bake cycle) the composite and vehicle body panel are bound together.
As also again previously described, the mat may again be configured by forming, wrapping or rolling about an axis prior to inserting or attaching into a cavity defined by a vehicle pillar or the like and prior to the secondary heating and expansion/sealing stage of the composite material. In this application, it is contemplated that the composite material may expand thermally according to its materially defined coefficient and in order to substantially fill and seal within the pillar, as well in specific instances to define a desired gap to provide for appropriate baffling of fluids through and out of the pillar.